Rewrite ${((3^{-6})(5^{-11}))^{9}}$ in the form ${3^n \times 5^m}$.
Solution: ${ ((3^{-6})(5^{-11}))^{9} = (3^{(-6)(9)})(5^{(-11)(9)})} $ ${\hphantom{ ((3^{-6})(5^{-11}))^{9}} = 3^{-54} \times 5^{-99}} $